In this Tuesday, June 17, 2014 image taken from video obtained from British Broadcaster Sky, which has been authenticated based on its contents and other AP reporting, Kurdish soliders aim their weapons towards positions held by fighters of the Islamic State of Iraq and the Levant near Jalula, Iraq. Kurdish security forces are engaged in gun battles with Sunni militants in the northern Iraqi town of Jalula, according to British Broadcaster Sky. Footage showed Kurdish fighters known as peshmerga using heavy artillery and rockets to attack militant positions on Tuesday. (AP Photo/Sky via AP video)

In this Tuesday, June 17, 2014 image taken from video obtained from British Broadcaster Sky, which has been authenticated based on its contents and other AP reporting, Kurdish soliders aim their weapons towards positions held by fighters of the Islamic State of Iraq and the Levant near Jalula, Iraq. Kurdish security forces are engaged in gun battles with Sunni militants in the northern Iraqi town of Jalula, according to British Broadcaster Sky. Footage showed Kurdish fighters known as peshmerga using heavy artillery and rockets to attack militant positions on Tuesday. (AP Photo/Sky via AP video)

In this Tuesday, June 17, 2014 image taken from video obtained from British Broadcaster Sky, which has been authenticated based on its contents and other AP reporting, a Kurdish solider fires his weapon towards positions held by fighters of the Islamic State of Iraq and the Levant near Jalula, Iraq. Kurdish security forces are engaged in gun battles with Sunni militants in the northern Iraqi town of Jalula, according to British Broadcaster Sky. Footage showed Kurdish fighters known as peshmerga using heavy artillery and rockets to attack militant positions on Tuesday. (AP Photo/Sky via AP video)

In this Tuesday, June 17, 2014 image taken from video obtained from British Broadcaster Sky, which has been authenticated based on its contents and other AP reporting, Kurdish pehsmerga forces leave a vehicle, near Jalula, Iraq. Kurdish security forces are engaged in gun battles with Sunni militants in the northern Iraqi town of Jalula, according to British Broadcaster Sky. Footage showed Kurdish fighters known as peshmerga using heavy artillery and rockets to attack militant positions on Tuesday. (AP Photo/Sky via AP video)

File – In this Monday, Oct. 6, 2003 file photo, an oil refinery is seen in the city of Beiji, home to Iraq’s largest oil refinery. On Wednesday, June 18, 2014, a top Iraqi security official said Islamic militants of the al-Qaida-inspired Islamic State of Iraq and the Levant laid siege to Iraq’s largest oil refinery late Tuesday night, threatening a facility key to the country’s domestic supplies as part of their ongoing lightning offensive across the country. The Beiji refinery accounts for a little more than a quarter of the country’s entire refining capacity and any lengthy outage at Beiji risks long lines at the gas pump and electricity shortages, adding to the chaos already facing Iraq. (AP Photo/Ivan Sekretarev, File)

File – In this Monday, Oct. 6, 2003 file photo, an abandoned watchtower and lines of barbed wire are seen surrounding Iraq’s largest oil refinery as smoke rises from a petroleum gas flare, in the city of Beiji, north of Baghdad. On Wednesday, June 18, 2014, a top Iraqi security official said Islamic militants of the al-Qaida-inspired Islamic State of Iraq and the Levant laid siege to Iraq’s largest oil refinery late Tuesday night, threatening a facility key to the country’s domestic supplies as part of their ongoing lightning offensive across the country. The Beiji refinery accounts for a little more than a quarter of the country’s entire refining capacity and any lengthy outage at Beiji risks long lines at the gas pump and electricity shortages, adding to the chaos already facing Iraq. (AP Photo/Ivan Sekretarev, File)

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BAGHDAD (AP) â€” Iraqi forces and Sunni militants battled fiercely for control of the nation’s largest oil refinery on Wednesday as Prime Minister Nouri al-Maliki went on a diplomatic offensive, reaching out in a televised address to try to regain support from the nation’s disaffected Sunnis and Kurds.

Meanwhile, the government asserted that it had retaken partial control of a strategic city near the border with Syria.

Al-Maliki’s conciliatory words, coupled with a vow to teach the militants a “lesson,” came as almost all Iraq’s main communities have been drawn into a spasm of violence not seen since the dark days of sectarian killings nearly a decade ago.

The U.S. has been pressing al-Maliki to adopt political inclusion and undermine the insurgency by making overtures to Iraq’s once-dominant Sunni minority, which has long complained of discrimination by his government and abuses by his Shiite-led security forces.

In Washington, President Barack Obama briefed leaders of Congress on options for quelling the al-Qaida-inspired insurgency, though White House officials said the president had made no decisions about how to respond to the crumbling security situation in Iraq. While Obama has not fully ruled out the possibility of launching airstrikes, such action is not imminent, officials said, in part because intelligence agencies have been unable to identify clear targets on the ground.

Al-Maliki, a Shiite, has rejected charges of bias against Iraq’s Sunnis and Kurds and has in recent days been stressing that the threat posed by the militant Islamic State of Iraq and the Levant, or ISIL, will affect all Iraqis regardless of their ethnic or religious affiliations. He also rejects any suggestion that the Islamic State and other extremist groups enjoy support by disaffected Sunnis fed up with his perceived discrimination.

In a move apparently designed to satisfy Obama’s demand for national reconciliation, al-Maliki expressed optimism in a televised address Wednesday over what he called the rise by all of Iraq’s political groups to the challenge of defending the nation against the militant threat.

The crisis has led Iraqis to rediscover “national unity,” he said.

“I tell all the brothers there have been negative practices by members